中国城市热电厂区域热制冷对温室气体减排的作用

一些欧洲与亚洲国家已发展了满足建筑冬季供暖的区域供热系统,并以独立的电力压缩式制冷用于夏季空调的使用.存在两套并行的供暖与制冷空调系统意味着需要大量的初期投资.因此城市能源系统规划建设应考虑保持城市热电厂在夏季仍采用热电联产生产,实现热电厂区域热制冷以满足建筑在夏季的空调供冷,以使热电厂全年以高效率的热电联产方式运行.这种热电厂冷热联供系统为建筑提供了可持续的能源供应方案.本文以2004年的热电联产实际数据为依据,综合考虑我国的社会与经济发展趋势,对三种不同发展情景下通过发展热电厂夏季热制冷可实现的温室气体减排能力进行了分析预测.     

我国供暖区热电厂集中供冷探讨

分析了我国一些城市使用电空调制冷所引发的问题,认为在一定条件下将热电联产改造为热电冷联产,利用热电厂的热量作为城市集中供冷的驱动能源会带来较好的社会综合效益。探讨了我国供暖区热电厂集中供冷的影响因素、限定条件、经济性、实施要点等内容,并提出了技术建议和政策建议。     

基于热电厂与热水管网的集中供冷新模式

常规的热水网热电联产集中供热系统往往只能冬季供热,而在非采暖季热水网基本闲置或仅供少量生活热水。本文介绍了一种利用热电联产集中供热系统实现夏季制冷的新模式:在热电厂设置汽轮机抽汽驱动的吸收式热泵,回收汽轮机乏汽或循环冷却水余热,梯级加热热网水;在用户热力站设置热水型吸收式制冷机和溶液调湿型空气处理机,承担用户夏季空调冷负荷。该方式夏季利用热电厂的高温热水驱动制取冷量,不但提高了集中供热系统的设备利用率,还可以减小因夏季空调用电造成的季节性峰谷差值,降低夏季城市的供电压力。     

冷热联供热网的用户回水加压泵方案

一、前言量的5％（凌晨）到100％间变化,每个用户的近几年,随着热电联产和城市集中供热循环量则会在0％至100％间变化。事业的发展,许多城市开始酝酿热电冷三联2.流量调整幅度大。供方式全面解决城市能源与环境问题。方案采暖系统往往采用质调节,部分负荷时之一是在热电厂产生高温水通过热网送到各将供水温度降低。为了避免垂直失调和水平建筑。在建筑内通过吸收式制冷机利用热水失调,总循环量不会降的太低。而采用吸收式为热源制冷为空调提供冷源,同时通过热交制冷的系统,为了保证制冷效率,不希望降低换器提供采暖和生活热水。对于不宜修建…     

天津市燃煤小锅炉并网方案的探讨

天津城市集中供热虽然起步较晚,但发展很快,截止2000年底,住宅供热面积为4225万m~2,市区住宅热化率为57.6％,其中集中供热面积为3911万m~2,集中供热率为53.28％。以前,我市在制定城市供热规划时以热电联产的热电厂的供热规划为主,以锅炉房供热作为调峰,在热电联产达不到的地区以锅炉房供热为主,缺少认真考虑远期热电联产和近期区域锅炉房如何相结合的过渡方案。当热电厂因种种因素建设缓慢而满足不了城市供热发展需要时,加上供热管理体制不完善,分散小锅炉房便大量兴建。针对燃煤小锅炉供热     

北方主要供暖方式的利弊

正主持人:我国北方地区供暖主要采用哪几种方式?陈振楼:我国基本的供热方式大致有三种:热电联产的集中供热,区域锅炉房为热源的集中供热,家庭燃煤炉。热电联产集中供热,目前华北地区大中型城市均有一个或几个热电厂为热源的热网,如北京市随着高碑店热电厂的并网和城区管网的进一步扩建和改造,供热面积可进一步发展到     

企业自备热电厂的节能性分析

以余姚市某化纤企业自备热电厂热电联产系统为研究对象,对其热、电负荷做了计算,同时用标准煤耗量和总热效率2个指标对系统进行节能性分析。分析结果表明:热电联产系统节能性要优于分产系统,实施热电联产后全厂总热效率提高27.3%,在企业年生产总量不变的条件下,年节约标准煤18125.55t,极大地节约运行成本。文章最后还指出该系统在夏季运行时热负荷减少导致发电量减少,并提出将系统改进为热电冷联产系统的建议。实行热电冷联产后,系统总热效率较原来夏季热电联产系统总热效率提高24.7%,系统节能性进一步提高。     

基于热电厂与热水管网的集中供冷模式

介绍了一种利用热电联产集中供热系统实现夏季供冷的模式,其特点是在热电厂设置汽轮机抽汽驱动的吸收式热泵,回收汽轮机乏汽或循环冷却水余热,梯级加热热网水;在用户热力站设置热水型吸收式制冷机和溶液调湿型空气处理机,承担用户夏季空调冷负荷。该方式夏季利用热电厂的高温热水驱动制冷机,可提高集中供热系统的设备利用率,降低夏季城市的供电负荷。     

关于发展热,电,冷联产联供的建议

热、电、冷联产联供，是在我国经济高速发展，人民生活水平不断提高的条件下，在热电联产集中供热的基础上发展起来的新型综合供热系统，由于它使用已有热源厂（热电厂、集中锅炉房或工业企业的余热）的蒸汽和热力管网，因而有投资省，提高热源厂夏季低谷的热负荷，减少城市空调制冷的用电量等优点，又由于澳化锂制冷机不用氯氟烃（俗称氟里昂）因而有利于环境保护，所以热、电、冷联供是节能、节电和有利环保的先进的技术，应积极宣传推广。1997年9月20—23日中国电机工程学会热电专业委员会，中国动力工程学会工厂动力与节能分会，热力专…     

热电冷联产系统节能性的(火用)分析

利用分析的方法,定义了等效发电效率,对常用热电冷联产系统形式的节能性进行了分析。认为相对于全国平均供电煤耗而言,热电冷联产系统的节能是有条件的,应选取合理的方式,优化设计和运行方案;相对于当前有些热电厂夏季负荷不足的情况,热电冷联产是节能的,在不同的情况下节能率在7.8%~39%之间。建议利用现有的热电联产条件,发展热电冷联产系统,提高现有热电厂的设备利用率和运行经济性。     

冷热联供系统的能耗估算

阐述了利用热电联产热、锅炉房供热和房热驱动的各种冷热联供系统的能耗估算方法,对热电联产情况考虑了汽轮机进排气参数等条件的变化对供热供冷能耗的影响,给出了一定条件下各种系统包括热泵系统的供热供冷一次能耗率,并与常规系统作了比较。     

下送上回通风方式供冷与供暖运行性能比较

下送上回通风方式目前得到了广泛的研究应用,其供冷运行时就是置换通风,但同样一套通风系统在一些地区的寒冷季节则有可能需要作供暖运行.为了获得下送上回通风系统在分别作供冷与供暖运行时的具体性能参数,本文应用实验测试与计算流体力学(CFD)模拟的方法研究了置于环境实验室内的某办公环境.研究中分析比较了该办公环境内的空气速度、温度以及追踪气体污染物的浓度分布.研究结果表明,下送上回通风方式作供冷运行时空气温度及污染物浓度分层现象明显,空气处于半混合状态,置换效果较好;作供暖运行时,温度及污染物浓度趋于均匀,通风系统性能接近于混合送风系统,不具备良好的抑制交叉污染的能力.     

A simulation appraisal of performance of different HVAC systems in an office building

The article reports on a simulation appraisal of energy consumption, energy costs and environment impact of three systems used for space heating, and space cooling of an office building in Kragujevac, Serbia. Three investigated systems are (1) a system with a natural gas boiler and convective baseboard heaters for water space heating and window air conditioners for air space cooling; (2) a system with a natural gas boiler and individual air reheaters for air space heating and a chiller plant for air space cooling; and (3) an air-to-air heat pump for air space heating, and cooling. The systems are modeled and simulated by using EnergyPlus software. After simulations, it is found that the first investigated system has the highest energy efficiency, the best economy, and the lowest environmental impact. That is because of the fact that the first system has water as a heating medium and uses predominantly natural gas as fuel. However, in future, when for generation the grid electrical energy requires less primary energy, and becomes decarbonized, the third system would be best to conserve energy resources and environment.     

Development of a radiant heating and cooling model for building energy simulation software

Efficient radiant heating and cooling systems are promising technologies in slashing energy bills and improving occupant thermal comfort in buildings with low-energy demands such as houses and residential buildings. However, the thermal performance of radiant systems in buildings has not been fully understood and accounted for in currently available building energy simulation software. The challenging tasks to improve the applicability of radiant systems are the development of an accurate prediction model and its integration in the energy simulation software. This paper addresses the development of a semi-analytical model for radiant heating and cooling systems for integration in energy simulation software that use the one-dimensional numerical modeling to calculate the heat transfer within the building construction assemblies. The model combines the one-dimensional numerical model of the energy simulation software with a two-dimensional analytical model. The advantage of this model over the one-dimensional one is that it accurately predict the contact surface temperature of the circuit-tubing and the adjacent medium, required to compute the boiler/chiller power, and the minimum and maximum ceiling/floor temperatures, required for moisture condensation (ceiling cooling systems), thermal comfort (heating floor systems) and controls. The model predictions for slab-on-grade heating systems compared very well with the results from a full two-dimensional numerical model.     

区域供冷系统能耗分析

针对区域供冷系统存在的能耗问题,通过对日本两个典型区域供冷项目具体案例的深入分析,指出其能耗水平,结合国内典型公共建筑分散供冷供暖系统的能耗数据,指出区域供冷高能耗的根源所在.在分析了国外一些成功区域供冷案例的成功之处后,进一步指出区域供冷遇到的各种问题,认为区域供冷系统节能的前提条件是具备高密度的冷负荷用户和足够量的廉价天然冷源.     

Utilization of wind energy in space heating and cooling with hybrid HVAC systems and heat pumps

Approximately one-third of the primary energy resources are consumed in space heating, cooling, and air-conditioning with a very low exergetic efficiency. The depleting nature of primary energy resources, negative environmental impact of fossil fuels and low exergetic efficiencies obtained in conventional space heating and cooling are the main incentives for developing alternative heating, ventilating, and air-conditioning (HVAC) techniques which can employ low density and interrupted energy sources. In this respect, in spite of difficulties primarily encountered in coupling wind energy with conventional space heating and cooling equipment, wind energy seems to be an exciting alternative provided that synectic combinations are pursued and applied. In this paper, a new wind turbine coupled hybrid HVAC system is presented, which consists of an optimum combination of convective and radiant heating and cooling systems with in-space thermal energy storage. A design case for a single family home is presented. In this study a 6 kW(e) wind turbine drives a ground source heat pump (GSHP) which is coupled to a hybrid HVAC system to satisfy the thermal loads of a 100 m² home. In this example, sensible heating and cooling loads are satisfied by the high mass radiant floor which matches the daily peak demand and the available peak wind energy. Latent heating and cooling loads, along with ventilation requirements are satisfied by a forced-air system. Variable radiant and convective split type of control is implemented, and both systems are served by the same GSHP which also satisfies the domestic hot water (DHW) demand.     

Verification of energy efficiency of district heating and cooling system by simulation considering design and operation parameters

This paper aims to verify the advantages of district heating and cooling (DHC) systems in terms of energy efficiency. From the measurement data, the parameters that characterize the energy efficiency of a heating/cooling plant are identified for DHC and an individual building. A simulation model that considers the difference in these parameters is developed. This model examines both the advantages and disadvantages of DHC systems and the effect of each parameter. The results show that the energy efficiency for cooling in DHC systems is superior to that in the case of individual cooling systems because of the “concentration effect” and “grade of operation”.     

建筑环境设计模拟分析软件DeST第9讲冷热源与水系统模拟分析(下)

冷热源系统是整个集中空调系统的核心,它决定了系统能否保障用户的冷热需求,是投资的主要部分,也是能源消耗的主要部分。同时冷热源产生的冷热量主要依靠水系统输配到各末端用户中去。因此冷热源与水系统的联合优化设计是整个空调系统设计过程中至关重要的环节。综述了目前冷热源与水系统联合模拟的现状,详细阐述了DeST模拟软件中冷源和水系统模拟所采用的的模型与模拟方法。通过介绍一个设计实例,指出了冷热源与水系统全工况模拟的应用范围和实际意义。     

A rapid calibration procedure and case study for simplified simulation models of commonly used HVAC systems

A rapid procedure for calibrating simplified building energy simulation models of commonly used HVAC systems has been developed. The procedure developed will allow building professionals to project annual cooling and heating energy consumption of buildings with multiple HVAC systems from short-term field measurement data. This paper describes the general calibration procedure developed, and demonstrates the use of the calibration procedure by applying it to an office building. The calibration methodology requires as little as two weeks of measured hourly heating and cooling consumption data. In the example presented, the simulation model was calibrated using only two weeks of measured heating and cooling data. After calibrating the simulation using this procedure, the RMSE is reduced significantly. The simulation calibrated to two weeks of measured data is then used to simulate the hourly consumption of the building for the year 2004. Comparison of the results of this simulation with the measured data gave monthly CV(RMSE) values of 10.3% and 3.7% for cooling and heating, respectively, which are both well below the 15% values considered acceptable in ASHRAE Guideline 14 [1]. It also shows monthly NMBE values of 2.2% and 1.4% for cooling and heating respectively.     

Influence of building parameters and HVAC systems coupling on building energy performance

The performance of different HVAC systems varies when coupled with different buildings. This paper examines the relationship between building heating and cooling load and subsequent energy consumption with different HVAC systems. Two common HVAC systems in use throughout the UK office building stock, variable air volume (VAV) system and fan coil (FC) with dedicated outside air system, have been coupled with a typical narrow plan office building with and without daylight control and for both cellular and open plan.The results presented in this paper clearly indicate that it is not possible to form a reliable judgment about building energy performance based only on building heating and cooling loads. For the two investigated systems, variable air volume system and fan coil with dedicated outside air system, the difference between system demand and building demand varied from over −40% to almost +30% for cooling and between −20% and +15% for heating. If a heat recovery unit is used, the difference in heating performance is even greater, rising to −70%.